Friday, May 30, 2014

Ancient Agony

I don’t know how or when she broke her leg; all I know is she miraculously survived this devastating injury. It wasn’t a simple fracture of the tibia or fibula. Somehow she sustained a midshaft femur fracture, which is not only life-threatening, but incredibly painful. It was a serious break. The broken ends of bone were knocked out of alignment, ending up side by side; the kind of fracture that can only be corrected surgically.
What force could have caused such an injury? During my years as a firefighter-paramedic, femur fractures were usually the result of an “auto vs. pedestrian” or a serious crash. It takes a lot of force to break the largest, strongest bone in the body.

But her injury was not from a car, nor from a crash, for this woman lived over seven thousand years ago along the east coast of Florida. Her skeleton was found among the ancient assemblage known as Windover, a site that has yielded a wealth of information about prehistoric Floridians.
Her bones speak of a hard life. The leg injury was but one of the maladies that plagued her and despite the fracture, she managed to survive for years afterward. The ragged bone ends eventually mended, a heavy knot of callus sealing them to each other, resulting in a shortened limb and a lifetime of limping that would have made her difficult life that much more challenging.

We can tell a lot about her through her well-preserved skeleton, buried, along with 167 others, in the base of a small pond near present-day Titusville. This mortuary pond held the bundled remains of a people who roamed the Florida peninsula thousands of years ago. Their bodies remained tucked beneath the surface until their accidental discovery in 1982.
After retiring from the Orlando Fire Department, I came to Florida State to earn a PhD, specializing in bioarchaeology and spending my years at FSU studying the skeletons from Windover. And what stories these skeletons have told…

Imagine this: It’s mid-August in Florida and the temperature is hovering around ninety-five degrees. The humidity has settled like a dense fog as the sun sets on this sweltering day. The mosquitos are rising in droves from the swamp as they seek out any bit of exposed flesh, and a late thunderstorm has left behind a stifling stillness. Oh, and I almost forgot… you’re lying on a mat, writhing in pain from a fractured femur.
Broken bones weren’t the only health challenges these ancient Floridians faced. You should see their teeth.

Envision your mouth if you’d never brushed or flossed (even worse, imagine your breath). But cavities and plaque were the least of their troubles. Attrition, or wearing down of the teeth, was rampant, as was tooth loss. If you were lucky enough to survive into your forties, the teeth you managed to hold onto were typically worn to the gum line from years of eating gritty, acidic foods and using your jaws as tools. Many people also suffered from infections. Abscesses burrowed into the bones of their jaws, inflaming them with pus and causing full-blown sepsis if the infection entered the bloodstream.
And speaking of infection… their mouths weren’t the only body parts affected. You may not realize it, but infection wreaks havoc on bone. It causes the outer layer of bone, or periosteum, to become inflamed and can even wheedle its way into the marrow cavity, where it can spread unchecked throughout the body.

And think how demanding their lives were. Hungry? Go hunt down your dinner or gather it from the forest. Thirsty? Trek to the nearest water source and hope it’s not infected with parasites. Need shelter? Better get to work on that thatch hut, which means gathering enough palm fronds to hold off a raging thunderstorm. Need to pee or poo? Get far enough from camp to avoid contaminating the soil you’ll be sleeping upon.
In other words, each of life’s necessities required work. The result? Plenty of wear and tear on the joints. And as the arthritis advanced, each and every chore became that much harder, requiring that much more effort.

We have it made. Modern life is infused with ways to make life easier. Cars, grocery stores, washing machines, and refrigerators enable us to drive, shop, clean, and store food. Not to mention life’s little luxuries, like clothes, bug spray, and toilet paper.
So the next time you gripe about the cable being out or the Internet being too slow, take a breath and think about those of our distant past. What they would have given for one day in our shoes.

If you'd like to read more about the fascinating Windover site, click here:

Friday, May 23, 2014

How to Cure a Corpse

If you’ve ever smelled a decaying corpse, you’ll appreciate the science of embalming. Nothing smells worse than a body in the full throes of decomposition. It’s a mélange of horrific odors: the gut-churning stench of putrid flesh mixed with a rank sweetness that clings to your mucous membranes. It’s a fetid gift that keeps on giving.

During my tenure as a firefighter/paramedic, we were often called to “check on the wellbeing of a patient.” In other words, “Grandpa hasn’t answered his phone in over a week. Can you guys swing by and check a pulse?”

As we’d pull up to the residence, we’d scan for newspapers. An accumulation on the front lawn was always a bad sign, as was a mailbox stuffed to overflowing. We’d approach the front door and pause to take a deep whiff. We could usually diagnose death by its odoriferous calling card (or as the medical examiners refer to it, the “smell of job security”).

So if a single body is capable of producing such rank odors, imagine a battlefield strewn with dead soldiers, their bloated bodies exploding under a scorching summer sun. Those were the conditions under which embalming first took hold on a grand scale.

But first, a quick retrospective… The Egyptians were embalming over eight thousand years ago as part of their intricate mummification process. After removing the brain and internal organs, the body was immersed in natron, a salt solution that would desiccate the tissues. Once the body was dried out, which usually took about a month, the wrapping of the body would commence. Egyptians believed a person’s soul would eventually return to his body, so it was only proper to preserve it for the soul’s homecoming. Unfortunately, only the wealthy were afforded proper mummification; the poor, they simply dunked in salt and hoped for the best.

Fast forward thousands of years to the bloody battlefields of America’s Civil War. It’s the 1860s and our nation is at war with itself. Union and Confederate soldiers are busy blasting each other to smithereens, resulting in a plethora of dead bodies that have no chance of keeping fresh for the long trip home. Mass graves were the usual solution. Large pits were dug and the bodies were laid to rest and quickly covered.

But as in so many realms of science, necessity was the mother of invention. Enter Dr. Thomas Holmes.

Dr. Holmes was a captain in the Army Medical Corps, assigned to Washington, D.C. He was the first to
practice embalming, which he achieved by injecting his “patients” with an arsenic solution that retarded the ravages of decomposition. His talents soon captivated President Lincoln, who was so enamored of the practice that he assigned Holmes and the Quartermaster Corps to provide embalming for Union soldiers and officers killed in battle. Holmes went on to embalm over four thousand before chucking his military career for a lucrative private practice.

So what is embalming and how is it achieved? Let’s explore.

Today, arsenic has been replaced by a formaldehyde solution (despite being deemed a carcinogen). Not only does it preserve the body, it also disinfects it. Disinfecting the corpse makes for safer handling; preserving the corpse makes it more appealing for those wishing to view the dead. It also provides a larger window in which to make funeral arrangements, freeing the undertakers from playing beat-the-clock against putrefaction.

Before the body is embalmed it is laid out, washed, and shaved, if necessary. The eyes are kept shut using eye caps, small plastic disks that are slipped under the eyelids. Perforations on the disks hold the lids in place, since nothing says “creepy” like a staring corpse. The mouth is closed with tacks that are placed in the upper and lower jaws and held together with wires. A special cream is then applied to the lips to hold them in place and prevent chapping.

Now the embalming can commence.

The embalming fluid enters the body via an incision into an artery; usually the carotid in the neck. A small pump holds the solution and is attached to the artery by a hose. A separate hose is inserted into a large vein, usually the femoral near the groin, and will empty into a nearby drain. The fluid (about three gallons) is pumped into the artery and circulated throughout the body, forcing out the blood and infusing the cells, before exiting through the hose in the vein. The process is complete when the entire blood volume is replaced by formaldehyde.

Idiot Alert!! There's a new trend in getting high: soaking cigarettes and joints in formaldehyde, which, when smoked, bring on hallucinations. Unfortunately, this also brings on seizures and coma, so play it safe and DON'T SMOKE ANYTHING!

But I digress... The incisions are closed and the pump removed, but one last step remains. A hollow tube formally called a trocar, which is attached to a suction unit, is inserted into the abdomen. With the flip of a switch, the gasses and liquids produced during early decomposition are magically sucked away and the belly is then flushed with a preservative. Now the body is properly embalmed and the technicians, wielding their combat-ready makeup kits, can move in to restore the corpse to its former lifelike splendor.

So now you know what awaits you, should you choose the traditional route of an open casket funeral. As for me? Harvest my organs, if possible, and throw me on the barbie. I’ve never been one for fuss and muss.

Here's a great book on the subject of all things "corpse."

Friday, May 16, 2014

Birthdays and Bones

Here's a question: how many of you sneak a peek when you're in the gym locker room? Be honest. I'm one of the few who openly admits I'm a gawker (of course, I do it with utmost discretion). The locker room affords the rare opportunity to see real bodies, not those computer enhanced, airbrushed renditions we see in the media. You get a unique double feature in the locker room: bodies of all ages and bodies that are naked (unfortunately in my locker rooms, they’re also all female, but you can’t win ‘em all). For someone like me, who’s enamored of form and function, it makes for some interesting viewing.
It’s astounding how the body morphs as we age. This morning at the gym, I wrapped up my workout and was cruising to the showers when I happened by the Jacuzzi. Percolating within the bubbly froth were six elderly ladies, happily chatting away as they simmered to pruned perfection. Gazing upon that veritable senior stew got me thinking about my own aging body. Sure, the mirror is a constant reminder of the ticking, gravitational clock, and our skin holds few secrets about the passing years, but how often do we contemplate the toll age takes on our skeletons? 
Let's take a quick glimpse at the life of our bones.

We tend to think of our skeleton as fixed and unchanging, that steely scaffold on which our flesh and blood is suspended. But our skeleton is a highly dynamic structure, constantly changing throughout our lifetime.

Bone is made up of two primary components: the large protein, collagen, which gives the bones their elasticity; and hydroxyapatite, the dense inorganic substance that provides their strength (pound for pound, bone is stronger than steel!). The duality of these two main ingredients is what allows bone to be strong yet somewhat flexible and this same successful recipe is found in all mammalian skeletons.
The typical adult sports 206 bones, yet we emerge from the womb with over three hundred. Where do the others go?

They don’t go anywhere. Many of the bones that make up the newborn skeleton originate in segments that fuse over time. Many baby bones also have yet to ossify (video!), meaning they are still primarily cartilage but will eventually turn to bone (that’s what makes infants so darn flexible). And some bones, such as your kneecap, won’t show up until after you are born.
The hand is a perfect example. A newborn’s hand will eventually ossify into the twenty-seven bones that form this remarkable appendage, and that, along with the twenty-six bones of each foot, make up over half of your entire skeleton!

Bones grow in two directions: they get thicker and they get longer. Length is acquired via the growth plates at the ends of bones. These plates, or epiphyses, will continue to add bone until growth ceases and the seam that separates the plate from the shaft eventually disappears. Since each bone fuses on its own schedule, they provide a handy means of determining the age of children at the time of death.
For example, say we find a skeleton whose bones are completely fused except for the collarbone. Since your collarbone is the last to fuse – usually not until you’re in your early twenties – we can surmise the individual was a young adult when they died.

Just because the bones have stopped growing does not mean they remain unchanged. In fact, once your skeleton stops growing, it begins the slow march toward death. The little metabolic factories that produce bone (the osteoblasts) begin to slow down, and if they can’t keep pace with the bone destroyers, or osteoclasts, bone density diminishes and the skeleton becomes frail. That’s why the elderly are prone to breaks – bone loss equals bone weakness, and fractures are the typical result ("I’ve fallen and I can’t get up.").

There are many factors (aside from the number of candles on your cake) that age a skeleton. Our genetics can help or hinder; changes in hormones can wreak havoc on bone density; and then there’s lifestyle, that most fundamental (and controllable) of causal factors. What we eat, how much we exercise, and what we smoke all affect our bones; something to think about the next time you’re lying on your couch, puffing away and munching Cheetos.
So be a good skeletal steward and take care of your bones. You only get one set per lifetime, so do everything you can to make it last.

Your bones will thank you.

Friday, May 9, 2014

Sex Evolves...

About a billion years ago, two organisms floating within the primordial soup bumped into each other and had sex. Voilà! The revolution that would be sexual reproduction was born and organisms throughout the world have been coupling ever since.
OK... it was a bit more complicated than that, so we'll break it down.
The world was a very different place when sex first arrived on the scene. The ozone was just forming, providing some protection against the sun's raging UV radiation; oxygen was up to ten percent, about half of what it is today; and the continents were clustered in a giant clump known as Rodinia.  The planet was inhabited by single-celled organisms, primarily green and red algae. Needless to say, it was a pretty monotonous place.

But big things were happening. The eukaryotes, those cells sporting a nucleus, had evolved and multicellular critters were about to burst onstage. Fast forward half a billion years to the dawning of the Paleozoic and suddenly, life as we know it (or at least life as the trilobites would know it) was in full swing.
And what role did sex play in all of this? A BIG ONE!!

Scientists are still puzzling out how organisms transitioned from asexual to sexual reproduction, but they take hints from the natural world. Some bacteria are able to exchange genetic information on a rudimentary level, and many critters, such as yeast, are able to switch back and forth between the two methods as conditions warrant. So the basic evolutionary mechanics of sex are slowly being teased apart.
Once it kicked in, sexual reproduction fueled natural selection, as it still does today. Instead of organisms making carbon copies of themselves and relying on the occasional mutation to provide an edge among their competition, sex added valuable variation to the mix. The genetic shuffling and recombination that takes place during sex affords greater variability, which allows greater flexibility in a changing world. Adaptability, pathogen resistance, and the buffering of harmful mutations are all enhanced through sexual reproduction. Instead of relying on a single genetic line, as asexual organisms do, genes provided by two parents offer a broader playing field on which evolution can run rampant.

So how does sex work? Well, the standard penis-in-the-vagina method we humans (and most mammals) employ is but one manner of achieving fertilization. Let's explore.
Sexual reproduction involves the union between the sex cells, or gametes, of two parent organisms. We'll start with the tried and true method of most mammals, intercourse.

For intercourse to work, you need a sender and a receiver. The sender is equipped with a tool for administration (aka, the penis) and the receiver provides a welcoming receptacle (the vagina). Insertion of the tool, followed by a bit of friction, results in a magical deposit (sperm), and if the timing is right, the sperm are greeted by an eager egg (or eggs, in many cases). From this point on, nature takes its course. The egg is fertilized and the zygote is launched on its path to personhood (or elephanthood, porcupinehood… You get the picture).
This is the typical mammalian recipe. However, nature wouldn’t be nature if it didn’t throw in a bit of variety. For those who lack a tool or a receptacle, or simply prefer less fuss and muss, there are other means of achieving fertilization.

For instance, take fish. Imagine a fish penis. Bet you can’t. That’s because most fish spawn, meaning the males and females have adopted a “hands-off” approach to reproduction (I think they’re on to something…). The female typically releases a cluster of eggs and the male then swims over them while discharging a milky little cloud of semen. From there, the eggs and sperm are on their own. But since there are over thirty thousand different species of fish swimming the planet, their crop-dusting method is apparently pretty effective.
So fertilization takes two main forms: internal (like us) or external (as in our fishy friends), with a few variations on these themes. And just as with most aspects of our anatomy and physiology, evolution via natural selection has tinkered, resulting in the most effective method of fertilization for each species.

Not that there aren’t problems, but at least we humans are rewarded with an orgasm (or multiples, on a good day!). But are we the only species that has sex for the sake of sex?
Most animals (as well as certain Republican politicians) engage in sex purely for reproductive purposes. There are just a few exceptions: humans, dolphins, and bonobos (pigmy chimpanzees). Like us, dolphins and bonobos are known to engage in sex merely for the fun of it. Scientists believe sex among dolphins and bonobos might serve some of the same purposes it does among us humans – forging bonds which then promote group cohesion (although I’m convinced the bonobos do it for kicks and giggles). Ironically, bonobos are also one of the few animals (besides us) that practice face-to-face sex. The majority of mammals are better suited for the less personal but oh-so-effective method of mating from the rear.
You’ll be happy to know that scientists are hard at work discovering all the positive effects of sex (don’t question their methods). Regular sex has been shown to improve sleep, reduce stress, increase blood flow to the brain and other organs, and even keep your ticker healthy.

So the next time you get lucky, pause for a moment and reflect on the billions of years of evolution that came before you (no pun intended…).

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Friday, May 2, 2014

Selecting for Sex

My first kiss took place beneath a lunchroom table. The object of my affection was Whit Winfrey, a beautiful, blonde boy with striking blue eyes and tan arms adorned with feather-soft, white hairs. I lured him under the table to show off to my girlfriends, who had the audacity to doubt my ability to snag a kiss amidst the glaring gaze of the lunchroom monitor.

I succeeded, Whit was baffled, and I smugly returned to my sandwich as my girlfriends looked on in awe. Such is love among fifth graders.

It amazes me that I can remember such detail about Whit’s beauty, especially since many of my boyfriends have faded into the dark recesses of my memory. Whit was the first in a long line of fair-haired boys (with a few brunettes sprinkled in for variety) and even today, I’m a sucker for the blondes. But why? Why do we prefer certain physical traits over others?

Close your eyes and think about what turns you on (please keep your hands where I can see them). Are you a breast man or is it long legs that float your boat. Ladies, do you like a hairy chest or prefer a baby-smooth landscape? We all have certain physical traits that appeal to us more than others. What you may not have considered during your lustful meditations is the role attraction plays in evolution.

There are three primary elements of evolution. The first is mutation, commonly referred to as “descent with modification.” Without subtle changes in the genetic code, the second element, natural selection, would have nothing to work on. A fixed and unchanging organism wouldn’t last long in the dynamic environment of earth, and it’s the chance mutations that happen to confer an advantage that enables them to take hold in a population.

The third element is sex, or more specifically, sexual selection. Sex is nothing new; it’s been around for about a billion years.

Prior to the advent of sex, organisms reproduced asexually and many still do today: bacteria, protists, some plants and fungi, and even some animals. There are many ways to do it (or should I say, not do it): fission, budding, and spore formation, to name a few. There’s also parthenogenesis, in which the embryo develops without fertilization. If you were an aphid, a water flea, a hammerhead shark, or a komodo dragon, you’d be able to fly solo when it came to procreating. Think of all you’d be missing...

The development of sex was a boon for evolution. It is believed the recombination that occurs when organisms reproduce sexually, and therefore exchange genetic material, may purge bad mutations from their DNA. Recombination also provides a buffer against harmful mutations, since you have a fifty-fifty chance of getting a “normal” copy of the gene from one of your parents (which is why inbreeding is not such a good idea). Sex may also help fight disease by promoting the evolution of new genetic defenses. So to state the obvious: sex is good.

But a big part of sex comes down to choosing a mate. Here’s where things get really interesting.

How and why we choose whom we choose is based on what we find attractive in a mate. For the most part, it’s all about “fitness.” Fitness, in the biological sense, refers to an organism’s ability to leave behind offspring. Fitter individuals, be they moose or mollusks, will leave behind more moose or mollusks than their less fit counterparts and, in many cases, it’s the females who will do the choosing. As you can imagine, fitness has a broad range of expression, depending upon which species you belong to.

Take that moose, for instance. A female moose is wise to choose a male who’s muscular (and therefore can outrun predators) and one who sports a large rack (bet you never thought you’d hear that in reference to a male). That large rack will enable him to out-compete rival males as they vie for females.

But here’s the conundrum: the wild and whacky world of sexual selection appears in many ways to conflict with the basic premise of evolution. Natural selection is supposed to favor those who are better adapted to survive, yet many physical attributes that crop up as the result of sexual selection actually reduce chances of survival by encumbering their owner with extraneous or physiologically expensive accoutrements (the peacock’s tail is the typical example) .

A moose may develop an enormous rack, which gives him an edge in combat displays, but it’s also pretty darn heavy, making it more difficult to outrun a predator. Same with that peacock. He may strut around and display his tail to lure a prospective hen, but try evading a coyote while dragging that feathery aphrodisiac. My money’s on the coyote.

Natural selection has come to terms with this predicament. If an individual can sport such elaborate ornamentation (be it a giant rack or a monstrous set of tail feathers) and still survive and reproduce successfully, that individual passes the ultimate fitness test and will usually go on to leave more offspring.

As for humans, fitness is still defined by physical traits that represent mating potential, whether it be a beefy, masculine male or a voluptuous, fertile female. But we are also cultural beings, and today, culture dictates much of what we consider desirable in a mate.

And among us westerners, seems all you need is a flashy car or enormous breasts and you’re in like Flynn.

Happy hunting!

Since you now understand the fundamentals of selection, next week we'll delve further into the evolution of sex itself. Stay tuned and have a great week.

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